The present methods are directed to applying effective amounts of clethodim and gibberellic acid to an area in need of improved weed control.
One of the major concerns of crop plant growers is the presence of undesired plants, such as weeds, in the area where the crop plant is grown. Weeds contribute to decreased crop yields because the crop plants must compete with weeds for the limited available resources such as sunlight, soil nutrients, and water. Weeds can also host pests that can increase disease rates in crop plants.
Post emergent weeds are an especially concerning issue for crop plant growers because the herbicide applied for weed control can damage the young crop plants. Growers have struggled to find methods of providing adequate post emergent weed control. One way of controlling weeds has been to apply clethodim as a foliar spray following weed emergence. Previously there was no way to increase the speed of clethodim's activity on grasses.
Johnsongrass, Sorghum halepense, is a grass that is considered a weed in crop plant growing areas. Johnsongrass is problematic because it grows and spreads rapidly in the crop plant growing area. Johnsongrass has also been known to develop resistance to the common herbicide glyphosate posing a serious control problem for crop plant growers. Volunteer glyphosate tolerant corn is another serious pest in crops.
Clethodim (2-[1-[[[(2E)-3-chloro-2-propen-1-yl]oxy]imino]propyl]-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one) is a cyclohexanedione herbicide and a lipid (fatty acid) inhibitor. Clethodim is an effective post-emergence herbicide that is effective against perennial and annual grasses, however, symptoms of injury are typically slow to develop and are often not present for 7 to 10 days following treatment.
Clethodim typically requires 14 to 21 days to kill Johnsongrass and corn. This kill delay allows for the grass to continue to steal resources from the crop plants for up to three weeks. In addition, after each treatment growers are unsure if another treatment is necessary for several weeks which could cause over or under treatment of the crop plant environment. Therefore there is a need in the art for a more effective method of Johnsongrass and corn control.
Another issue is that when clethodim is tank mixed with herbicides to control broadleaf plants, the herbicides may antagonize the activity of clethodim on grassy weeds. It is commonly known that certain classes of broadleaf herbicides can reduce the activity of post emergence grass herbicides such as clethodim.
As explained above, there is a need in the art for a highly effective and safe post emergence weed control method, especially for the treatment of Johnsongrass.